The mid 1890s witnessed the start of a new era in British music criticism heralded by George Bernard Shaw. A preliminary study of the nineteenth-century critical context provides some reasons for its emergence. The new temper was defined by two critics: John F. Runciman. the self-appointed leader of the New critics. and the Rationalist Ernest Newman. Henry Hadow's Studies in Modern Music set a new standard and added impetus to discussion of critical theory. Several other critics associated with Oxford, including Parry, Tovey, Walker and Colles, formed a body of opinion that shared common values and continued a tradition stemming from Victorian writers such as Grove and Stainer. Discussions of critical theory, especially those of Newman and M. D. Calvocoressi. are given prominence. Two new trends emerged after the First World War. The first, a reaction against the German repertoire, focused on Stravinsky and the composers associated with Diaghilev's Ballets Russes. Foremost among those who championed the aesthetic of 'objective empiricism' were Edwin Evans and Leigh Henry. A second and more conservative tendency carne predominantly from two composer-critics associated with Philip Heseltine's journal of the 1920s. The Sackbut: Cecil Gray and K. S. Sorabji. Constant Lamben continued along broadly similar lines to Gray during the 1930s, notably in his Music Ho!. and is included as a member of the Sackbut coterie. Contrast between the criticism of Eric Blom and that of the poet W. J. Turner demonstrates the range of independent thought characteristic of the new era. Consideration of individual endeavour rather than collective trends of critical thought provides the method of documentation. The thesis attempts to elucidate the diversity of critical views without refuting a critic or entering into a polemical discourse. while in no way shirking the responsibility of arriving at an assessment of his position and achievement. Certain recurrent issues. including those surrounding Romanticism. nationalism and the rise of modernism. reflect the primary concerns of the period. A table showing music critics of leading British newspapers and a selected chronological list of one hundred books of music criticism published in Britain between 1890 and 1950 are contained in the appendices.